docs: def get_irradiance_value(self, month, day, hour):
          """Get direct and diffuse irradiance values for a point in time."""
          dt = DateTime(month, day, hour, leap_year=self.is_leap_year)
          count = int(dt.hoy * self.timestep)
          return self.direct_normal_irradiance[count], \
              self.diffuse_horizontal_irradiance[count]